
export const  getScrollTop=()=>{
  　　var scrollTop = 0, bodyScrollTop = 0, documentScrollTop = 0;
  　　if(document.body){
  　　　　bodyScrollTop = document.body.scrollTop;
  　　}
  　　if(document.documentElement){
  　　　　documentScrollTop = document.documentElement.scrollTop;
  　　}
  　　scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;
  　　return scrollTop;
  }



  //文档的总高度

  export const  getScrollHeight=()=>{
  　　var scrollHeight = 0, bodyScrollHeight = 0, documentScrollHeight = 0;
  　　if(document.body){
  　　　　bodyScrollHeight = document.body.scrollHeight;
  　　}
  　　if(document.documentElement){
  　　　　documentScrollHeight = document.documentElement.scrollHeight;
  　　}
  　　scrollHeight = (bodyScrollHeight - documentScrollHeight > 0) ? bodyScrollHeight : documentScrollHeight;
  　　return scrollHeight;
  }



  //浏览器视口的高度

  export const  getWindowHeight=()=>{
  　　var windowHeight = 0;
  　　if(document.compatMode == "CSS1Compat"){
  　　　　windowHeight = document.documentElement.clientHeight;
  　　}else{
  　　　　windowHeight = document.body.clientHeight;
  　　}
  　　return windowHeight;
  }
